Noise Countermeasures - Epson RC180 Manual

Setup & Operation 3. Installation

3.5 Noise Countermeasures

To minimize electrical noise conditions, the following items must be observed in the
system's cable wiring:
To minimize electrical noise condition, be sure of followings for wiring.
- The earth wire of the power supply should be grounded. (Ground resistance: 100 Ω or
less) It is important to ground the frame of Controller not only for prevention from
electric shock, but also for reducing the influence of electric noise around the
Controller.
Controller's power cable to the ground terminal of the factory power supply. For
details about the plug and AC power cable, refer to the Setup & Operation 3.3 Power
Supply.
- Do not tap power from a power line that connects to any equipment which may cause
noise.
- When you tap power for the Controller and the single-phase AC motor from the same
power line, change the phase of one or the other. Ensure that they will not be the
same phase.
- Use a twisted pair motor power line.
- Do not run AC power lines and DC power lines
in the same wiring duct, and separate them as far
as possible.
motor power line and the Controller power line as
far as possible from the sensor or valve I/O lines;
and do not bundle both sets of wiring with the
same cable tie. If more than one duct/cable must
cross
perpendicularly.
shown in the right figure.
- Wire as short as possible to the I/O connector and EMERGENCY connector. Use a
shielded cable and clamp the shield to the attached connector interior. Make sure to
keep away from the peripheral noise source as far as possible.
- Make sure that the induction elements used to connect to the Controller's I/O (such as
relays and solenoid valves) have surge suppressors. If an induction element without a
surge suppressor is used, make sure to connect a rectifying diode located at the
induction element in parallel with it. In selecting a rectifying diode, make sure that it
can handle the voltage and current incurred by the induction load.
- To start and change revolutions of the conveyer's (or the like's) AC motor (ex: an
induction motor or three-phase induction motor) regularly or abruptly, make sure to
install a spark suppressor between the wires. The spark suppressor is more effective
when placed closer to the motor.
- As they are easily influenced by static electricity or the noise from power source, keep
cable such as USB, Ethernet, RS-232C, or fieldbus away from peripheral noise sources.
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Therefore, be sure to connect the earth wire (yellow/green) of the
For example, separate the AC
each other, they
The preferable example is
should cross
AC Line duct
As far as
possible
DC line duct
RC180 Rev.17